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getting problem during simulation of sc integrator (Read 3512 times)
sourav
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getting problem during simulation of sc integrator
Nov 01st, 2012, 2:28am
 
Hi
I am getting unexpected output while simulating a SC integrator using a verilog-a model of opamp. I have tested a SC inverting gain stage and got desirable output Smiley. For that circuit I have discharged the feedback capacitor in each clock pulse.
But for integrator circuit we need to keep the charge of feedback capacitor. When I am doing  not discharging the feedback capacitor I am getting  :-/unexpected output(like in KV range as I am not using opamp saturation condition).

I think this is probably due to no feedback at DC. Can anyone suggest anything about the circuit Cry.

Thank you
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ywguo
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Re: getting problem during simulation of sc integrator
Reply #1 - Jan 28th, 2013, 6:32pm
 
HI sourav,

You said that the output was in kV range as the opamp did not have saturation condition. Did the opamp have soft limiting of output voltage?

If you post the code or block diagram of your opamp/sc-integrator, it maybe helpful for you to get fast response.

Best Regards,
Yawei
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Ken Kundert
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Re: getting problem during simulation of sc integrator
Reply #2 - Jan 28th, 2013, 10:40pm
 
Why don't you skip dc. If you are using Spectre, set the transient option skipdc=yes.

-Ken
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